[BEAM-5878] Support DoFns with Keyword-only arguments in Python 3.

• Type: Sub-task
• Status: Triage Needed
• Priority: P3
• Resolution: Unresolved
• Fix Version/s: 2.18.0
• Component/s: sdk-py-core
• Assignee: Unassigned
• Reporter: Valentyn Tymofieiev
• Created: 26/Oct/18 22:26
• Updated: 13/Apr/23 10:58

Description

Python 3.0 adds a possibility to define functions with keyword-only arguments.

Currently Beam does not handle them correctly. ruoyu pointed out one place in our codebase that we should fix: in Python in 3.0 inspect.getargspec() will fail on functions with keyword-only arguments, but a new method inspect.getfullargspec() supports them.

There may be implications for our (best-effort) type-hints machinery.

We should also add a Py3-only unit tests that covers DoFn's with keyword-only arguments once Beam Python 3 tests are in a good shape.

Issue Links

• blocks: BEAM-7950 Remove the Python 3 warning as it has already been supported
• is blocked by: BEAM-8397 DataflowRunnerTest.test_remote_runner_display_data sometimes fails due to infinite recursion during pickling on Python 3.7.
• links to: GitHub Pull Request #6781
• links to: GitHub Pull Request #8505
• links to: GitHub Pull Request #8750
• links to: GitHub Pull Request #9237
• links to: GitHub Pull Request #9517
• links to: GitHub Pull Request #9686
• links to: GitHub Pull Request #17509